- Chemoenzymatic polycondensation of para-benzylamino phenol
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Para-Benzylamine substituted oligophenol was synthesized via enzymatic oxidative polycondensation of 4-(benzylamino)phenol (BAP). Polymerization involved only the phenolic moiety without oxidizing the sec-amine (benzylamine) group. Chemoselective polycondensation of BAP monomer using HRP enzyme yielded oligophenol with sec-amine functionality on the side-chain. Effects of various factors including solvent system, reaction pH and temperature on the polycondensation were studied. Optimum polymerization process with the highest yield (63 %) and molecular weight (Mn = 5000, degree of polymerization ≈ 25) was achieved using the EtOH/buffer (pH 5.0; 1 : 1 vol. ratio) at 25 °C in 24 h under air. Characterization of the oligomer was accomplished by 1H NMR and 13C NMR, Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), ultraviolet-visible spectroscopy (UV-Vis), cyclic voltammetry (CV) and thermogravimetric analysis (TGA). The polymerization process involved the elimination of hydrogen from BAP, and phenolic-OH end groups of the oligo(BAP), confirmed using 1H NMR and FT-IR analyses. The oligomer backbone possessed phenylene and oxyphenylene repeat units, and the resulting oligomer was highly soluble in common organic solvents such as acetone, CHCl3, 1,4-dioxane, N,N-dimethylformamide (DMF), tetrahydrofurane (THF) and dimethylsulfoxide (DMSO). Oligo(BAP) was thermally stable and exhibited 5 % and 50 % mass loss determined by thermogravimetric analysis at 247°C and 852°C, respectively.
- Yildirim, Pinar,Gokturk, Ersen,Turac, Ersen,Demir, Haci O,Sahmetlioglu, Ertugrul
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- Unprecedented catalytic performance in amine syntheses: Via Pd/g-C3N4 catalyst-assisted transfer hydrogenation
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The preparation of amine compounds is very important for both the chemical industry and renewable feedstock processing. Nevertheless, difficulties remain in finding a catalytic system that is sufficiently active and environmentally benign for producing amine compounds. In this work, we report that g-C3N4 nanosheets as support materials can significantly boost the efficiency of Pd nanoparticles for the reduction of nitro compounds to primary amines. Using formic acid as a hydrogen donor and water as a solvent, the optimized 5 wt% Pd/g-C3N4 catalyst exhibited an unprecedented performance in the conversion of nitrobenzene into aniline (achieving almost full conversion with an extremely high turnover frequency of 4770 h-1 at room temperature), yielding the best activity ever reported for heterogeneously catalyzing nitro compound reduction. Pd/g-C3N4 catalyst was also active for the one-pot reductive amination of carbonyl compounds with nitro compounds to obtain the corresponding secondary amines with excellent selectivity (>90%). We proposed that the protic N-H+ and hydridic Pd-H- on Pd/g-C3N4 are the active species for the transfer hydrogenation reaction of nitro compounds. Furthermore, Pd/g-C3N4 catalyst was highly stable with a wide scope in the syntheses of various amine compounds. This work will open up a new approach for the transfer hydrogenations of nitro compounds to produce primary or secondary amines in green chemistry.
- Xu, Xingliang,Luo, Jiajun,Li, Liping,Zhang, Dan,Wang, Yan,Li, Guangshe
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- Direct one-pot reductive amination of aldehydes with nitroarenes in a domino fashion: Catalysis by gum-acacia-stabilized palladium nanoparticles
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(Figure Presented) This note describes the direct reductive amination of carbonyl compounds with nitroarenes using gum acacia-palladiumnanoparticles, employing molecular hydrogenas the reductant. This methodology is found to be applicable to both aliphatic and aromatic aldehydes and a wide range of nitroarenes. The operational simplicity and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of carbonyl compounds.
- Sreedhar,Surendra Reddy,Keerthi Devi
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- Highly selective room-temperature copper-catalyzed C-N coupling reactions
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Through the use of cyclic β-diketones as supporting ligands, the copper-catalyzed coupling of aryl iodides with aliphatic amines occurs at room temperature in as little as 1 h. These high reaction rates allow for the coupling of a wide range of aryl and heteroaryl iodides at room temperature. This method is highly tolerant of a number of reactive functional groups, including -Br and aromatic -NH2 as well as phenolic and aliphatic -OH. The high selectivity of the CuI-β-diketone catalyst for aliphatic amines represents a useful complement to the palladium-based methods. Copyright
- Shafir, Alexandr,Buchwald, Stephen L.
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- Simple reversible fixation of a magnetic catalyst in a continuous flow system: Ultrafast reduction of nitroarenes and subsequent reductive amination using ammonia borane
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Continuous reductive amination of aldehydes with nitroarenes over a Pd-Pt-Fe3O4 catalyst was performed. We used NH3BH3 as not only a hydrogen source for nitro reduction, but also a reductant for imine reduction. Secondary aromatic amines were obtained in the continuous flow reaction in good to excellent yields.
- Byun, Sangmoon,Cho, Ahra,Kang, Dong Yun,Kim, B. Moon,Kim, Ha Joon,Kim, Hong Won,Kim, Seong Min,Lei, Cao,Park, Jin Kyoon
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- Ultrathin platinum nanowire catalysts for direct C-N coupling of carbonyls with aromatic nitro compounds under 1 bar of hydrogen
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Traditionally important in the pharmaceutical, agrochemical, and synthetic dye industries, C-N coupling has proved useful for the preparation of a number of valuable organic compounds. Here, a new method for the direct one-pot reductive C-N coupling from carbonyl and aromatic nitro compounds is described. Employing ultrathin platinum nanowires as the catalyst and hydrogen as the reducing agent, N-alkylamines were achieved in high yields. Debenzylation products were not detected after prolonged reaction times. Time-dependent analysis, ReactIR spectroscopy and DFT calculations revealed that the C-N coupling proceeded through a different mechanism than traditional "reductive amination." N-Alkylamines were directly obtained by intermolecular dehydration over platinum nanowires under a hydrogen atmosphere, instead of intramolecular water elimination and imine hydrogenation.
- Hu, Lei,Cao, Xueqin,Ge, Danhua,Hong, Haiyan,Guo, Zhiqiang,Chen, Liang,Sun, Xuhui,Tang, Jianxin,Zheng, Junwei,Lu, Jianmei,Gu, Hongwei
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- One-pot synthesis of secondary amine via photoalkylation of nitroarenes with benzyl alcohol over Pd/monolayer H1.07Ti1.73O4·H2O nanosheets
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The photoalkylation of nitroarenes with benzyl alcohols in one pot at room temperature and 1 atm N2 was achieved over the Pd/H1.07Ti1.73O4·H2O nanosheets. The sample shows efficient photocatalytic activity with high conversion of nitrobenzene (99%) and selectivity of secondary amine (85%). This flexible photocatalytic system is also applicable to other nitroarenes with high efficiency. Results of in situ FTIR, DRS, and in situ ESR revealed that the benzyl alcohol and nitrobenzene molecules can bind with the surface Lewis and Br?nsted acid sites in the catalyst via the H–O?Ti and NO2?H–O–Ti species. The formation of surface coordination species results in not only the activation of reactant molecules via surface electron transfer, but also the expanded visible light absorption of the catalyst. Moreover, in situ ESR suggested that the surface coordination can also facilitate the formation of oxygen vacancies in catalysts, which can greatly promote the exposure of Lewis sites and enhance the activation of reactant molecules. Finally, a possible hydrogen transfer strategy over the sample is proposed on a molecular level.
- Song, Yujie,Wang, Hao,Liang, Shijing,Yu, Yan,Li, Liuyi,Wu, Ling
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- Direct reductive amination of aldehydes and ketones mediated by a thiourea derivative as an organocatalyst
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The direct reductive arylamination of arylaldehydes and ketones has been achieved using a selective imine activation by a hydrogen bond of a thiourea derivative. This mild, acid- and metal-free process requires a catalytic amount of N N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, the Hantzsch 1,4-dihydropydine diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate as hydride source and activated 5A-molecule sieve as dehydrant. The method is adaptable for the synthesis of various amines.
- Huang, Yi-Bo,Cai, Chun
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- Green synthesis and catalytic properties of palladium nanoparticles for the direct reductive amination of aldehydes and hydrogenation of unsaturated ketones
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This paper reports on the synthesis and use of palladium nanoparticles as heterogeneous catalysts for the reductive amination of aldehydes and hydrogenation of unsaturated ketones. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered and reused several times without significant loss of catalytic activity. This journal is
- Nasrollahzadeh, Mahmoud
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- Efficient photocatalytic one-pot hydrogenation and N-alkylation of nitrobenzenes/benzonitriles with alcohols over Pd/MOFs: Effect of the crystal morphology & “quasi-MOF” structure
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One-pot multi-step reactions over visible-light induced catalysis feature the sustainable green process. Here, ligand structure change and 2-MI coordinated modulation were adapted to adjust the crystal size, morphology and crystalline structure of Fe-MOFs; double solvent impregnation was employed for the Pd loading; “quasi-MOF” materials with retained morphology were formed with calcination under N2. Above modified materials were employed as multifunctional photocatalysts for highly efficient one-pot hydrogenation and N-alkylation of nitrobenzenes or benzonitriles with alcohols after in situ Pd photoreduction. Photocatalytic performance was evidently affected by the Fe-MOFs crystal size, morphology, crystalline structure alteration and “quasi-MOF” construction. One-pot hydrogenation and N-alkylation of benzonitriles with alcohols was achieved with excellent catalytic performance firstly in heteroegeneous catalysis. Reaction mechanism was proposed with the assistance of in situ DRIFTS.
- Bian, Fengxia,Cheng, Hongmei,Jiang, Heyan,Liu, Xingyan,Long, Xingyu,Yang, Chaofen
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- An efficient, recoverable fluorous organocatalyst for direct reductive amination of aldehydes
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A commercially available perfluorooctyl aniline and phenyl isothiocyanate were reacted under mild conditions to give 1-[4-(perfluorooctyl)phenyl]-3- phenylthiourea as an analogue of thiourea-based organocatalyst. This fluorous organocatalyst was successfully employed to direct reductive amination of aldehydes. It could be readily separated from reaction product by fluorous solid phase extraction for direct use.
- Huang, Yi-Bo,Yi, Wen-Bin,Cai, Chun
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- Porous polymeric ligand promoted copper-catalyzed C-N coupling of (hetero)aryl chlorides under visible-light irradiation
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A porous polymeric ligand (PPL) has been synthesized and complexed with copper to generate a heterogeneous catalyst (Cu@PPL) that has facilitated the efficient C-N coupling with various (hetero)aryl chlorides under mild conditions of visible-light irradiation at 80 °C (58 examples, up to 99% yields). This method could be applied to both aqueous ammonia and substituted amines, and is compatible to a variety of functional groups and heterocycles, as well as allows tandem C-N couplings with conjunctive dihalides. Furthermore, the heterogeneous characteristic of Cu@PPL has enabled a straightforward catalyst separation in multiple times of recycling with negligible catalytic efficiency loss by simple filtration, affording reaction mixtures containing less than 1 ppm of Cu residue. [Figure not available: see fulltext.]
- Wang, Erfei,Chen, Kaixuan,Chen, Yinan,Zhang, Jiawei,Lin, Xinrong,Chen, Mao
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- Cobalt encapsulated in N?doped graphene sheet for one-pot reductive amination to synthesize secondary amines
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To develop an efficient base-metal reductive amination catalyst for synthesis of secondary amines is still a major challenge. In this study, an efficient N-doped graphene sheet-coated cobalt catalyst (Co@CN-800) was developed through a simple pyrolysis process, which could gave 99.5 % yield of N-benzylaniline by one-pot reductive amination of nitrobenzene with benzaldehyde during at least 5 cycles. Catalyst characterization and control experiments confirmed that the robust catalytic performance of the catalyst is probably due to the synergy effect of in situ generated Co-Nx encapsulated in N?doped graphene layer and appropriate meso-pore structure. Additionally, The substrate adaptability of the catalyst was proved since a variety of corresponding secondary amines were smoothly obtained under relatively mild conditions, which makes the secondary amine synthesis strategy based on Co@CN-800 shows excellent application prospect.
- Liu, Lin,Li, Wenxiu,Qi, Ran,Zhu, Qingqing,Li, Jing,Fang, Yuzhen,Kong, Xiangjin
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- Scalable preparation of stable and reusable silica supported palladium nanoparticles as catalysts for N-alkylation of amines with alcohols
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The development of nanoparticles-based heterogeneous catalysts continues to be of scientific and industrial interest for the advancement of sustainable chemical processes. Notably, up-scaling the production of catalysts to sustain unique structural features, activities and selectivities is highly important and remains challenging. Herein, we report the expedient synthesis of Pd-nanoparticles as amination catalysts by the reduction of simple palladium salt on commercial silica using molecular hydrogen. The resulting Pd-nanoparticles constitute stable and reusable catalysts for the synthesis of various N-alkyl amines using borrowing hydrogen technology without the use of any base or additive. By applying this Pd-based catalyst, functionalized and structurally diverse N-alkylated amines as well as some selected drug molecules were synthesized in good to excellent yields. Practical and synthetic utility of this Pd-based amination protocol has been demonstrated by upscaling catalyst preparation and amination reactions to several grams-scales as well as recycling of catalyst. Noteworthy, this Pd-catalyst preparation has been up-scaled to kilogram scale and catalysts prepared in both small (1 g) and large-scale (kg) exhibited similar structural features and activity.
- Alshammari, Ahmad S.,Natte, Kishore,Kalevaru, Narayana V.,Bagabas, Abdulaziz,Jagadeesh, Rajenahally V.
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p. 141 - 149
(2020/01/06)
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- Synthesis and in vitro evaluation of novel non-oximes for the reactivation of nerve agent inhibited human acetylcholinesterase
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Since several decades oximes have been used as part of treatment of nerve agent intoxication with the aim to restore the biological function of the enzyme acetylcholinesterase after its covalent inhibition by organophosphorus compounds such as pesticides and nerve agents. Recent findings have illustrated that, besides oximes, certain Mannich phenols can reactivate the inhibited enzyme very effectively, and may therefore represent an attractive complementary class of reactivators. In this paper we further probe the effect of structural variation on the in vitro efficacy of Mannich phenol based reactivators. Thus, we present the synthesis of 14 compounds that are close variants of the previously reported 4-amino-2-(1-pyrrolidinylmethyl)-phenol, a very effective non-oxime reactivator, and 3 dimeric Mannich phenols. All compounds were assessed for their ability to reactivate human acetylcholinesterase inhibited by the nerve agents VX, tabun, sarin, cyclosarin and paraoxon in vitro. It was confirmed that the potency of the compounds is highly sensitive to small structural changes, leading to diminished reactivation potency in many cases. However, the presence of 4-substituted alkylamine substituents (as exemplified with the 4-benzylamine-variant) was tolerated. More surprisingly, the dimeric compounds demonstrated non-typical behavior and displayed some reactivation potency as well. Both findings may open up new avenues for designing more effective non-oxime reactivators.
- Horn, Gabriele,Worek, Franz,de Koning, Martijn C.,van Grol, Marco
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- Continuous nitro-reduction and reductive amination reaction using ammoniaborane and magnetic nanoflakes immobilized through external magnetic force
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The present invention provides: a method of continuous reduction of a nitro compound which comprises continuously contacting a magnetic catalyst with a nitro compound and a reducing agent to reduce the nitro compound and continuously supplying an aldehyde compound thereto to continuously produce a secondary amine compound by conducting a reductive amination reaction; and an apparatus for the same.COPYRIGHT KIPO 2019
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Paragraph 0042-0052; 0103-0107
(2019/07/03)
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- Visible-Light Photocatalytic Synthesis of Amines from Imines via Transfer Hydrogenation Using Quantum Dots as Catalysts
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CdSe/CdS core/shell quantum dots (QDs) can be used as stable and highly active photoredox catalysts for efficient transfer hydrogenation of imines to amines with thiophenol as a hydrogen atom donor. This reaction proceeds via a proton-coupled electron transfer (PCET) from the QDs conduction band to the protonated imine followed by hydrogen atom transfer from the thiophenol to the α-aminoalkyl radical. This precious metal free transformation is easy to scale up and can be carried out by a one-pot protocol directly from aldehyde, amine, and thiophenol. Additional advantageous features of this protocol include a wide substrate scope, high yield of the amine products, extremely low catalyst loading (0.001 mol %), high turnover number (105), and the mild reaction conditions of using visible light or sun light at room temperature in neutral media.
- Xi, Zi-Wei,Yang, Lei,Wang, Dan-Yan,Pu, Chao-Dan,Shen, Yong-Miao,Wu, Chuan-De,Peng, Xiao-Gang
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p. 11886 - 11895
(2018/09/25)
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- Metal- and Base-Free Room-Temperature Amination of Organoboronic Acids with N-Alkyl Hydroxylamines
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We have found that readily available N-alkyl hydroxylamines are effective reagents for the amination of organoboronic acids in the presence of trichloroacetonitrile. This amination reaction proceeds rapidly at room temperature and in the absence of added metal or base, it tolerates a remarkable range of functional groups, and it can be used in the late-stage assembly of two complex units.
- Sun, Hong-Bao,Gong, Liang,Tian, Yu-Biao,Wu, Jin-Gui,Zhang, Xia,Liu, Jie,Fu, Zhengyan,Niu, Dawen
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supporting information
p. 9456 - 9460
(2018/07/29)
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- Main-Group-Catalyzed Reductive Alkylation of Multiply Substituted Amines with Aldehydes Using H2
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Given the growing demand for green and sustainable chemical processes, the catalytic reductive alkylation of amines with main-group catalysts of low toxicity and molecular hydrogen as the reductant would be an ideal method to functionalize amines. However, such a process remains challenging. Herein, a novel reductive alkylation system using H2 is presented, which proceeds via a tandem reaction that involves the B(2,6-Cl2C6H3)(p-HC6F4)2-catalyzed formation of an imine and the subsequent hydrogenation of this imine catalyzed by a frustrated Lewis pair (FLP). This reductive alkylation reaction generates H2O as the sole byproduct and directly functionalizes amines that bear a remarkably wide range of substituents including carboxyl, hydroxyl, additional amino, primary amide, and primary sulfonamide groups. The synthesis of isoindolinones and aminophthalic anhydrides has also been achieved by a one-pot process that consists of a combination of the present reductive alkylation with an intramolecular amidation and intramolecular dehydration reactions, respectively. The reaction showed a zeroth-order and a first-order dependence on the concentration of an imine intermediate and B(2,6-Cl2C6H3)(p-HC6F4)2, respectively. In addition, the reaction progress was significantly affected by the concentration of H2. These results suggest a possible mechanism in which the heterolysis of H2 is facilitated by the FLP comprising THF and B(2,6-Cl2C6H3)(p-HC6F4)2.
- Hoshimoto, Yoichi,Kinoshita, Takuya,Hazra, Sunit,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 7292 - 7300
(2018/06/01)
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- One-pot Reductive Amination of carbonyl Compounds with Nitro Compounds by Transfer Hydrogenation over Co–Nx as catalyst
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A new method was developed for the synthesis of secondary amines through the one-pot reductive amination of carbonyl compounds with nitro compounds using formic acid as the hydrogen donor over a heterogeneous non-noble-metal catalyst (Co-Nx/C-800-AT, generated by the pyrolysis of the cobalt phthalocyanine/silica composite at 800°C under a N2 atmosphere and subsequent etching by HF). Both nitrogen and cobalt were of considerable importance in the transfer hydrogenation reactions with formic acid.
- Zhou, Peng,Zhang, Zehui
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p. 1892 - 1897
(2017/05/16)
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- One-pot reductive amination of carbonyl compounds with nitro compounds with CO/H2O as the hydrogen donor over non-noble cobalt catalyst
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The one-pot reductive amination of carbonyl compounds with nitro compounds over heterogeneous non-noble metal catalysts was developed for the first time by transfer hydrogenation with CO/H2O as the hydrogen donor. Nitrogen-doped carbon supported cobalt nanoparticles were observed to be active toward this reaction, affording structurally-diverse secondary amines with high yields. Kinetic studies revealed that the transfer hydrogenation of imines (C[dbnd]N bonds) was the rate-determining step. Reaction mechanism studies indicated that both nitrogen and cobalt nanoparticles were important for the transfer hydrogenation with CO/H2O to generate the proton (N[sbnd]H+) and hydride (Co[sbnd]H?) as the active species. Furthermore, the heterogeneous cobalt catalyst was highly stable without the loss of its catalytic activity during the recycling experiments.
- Zhou, Peng,Yu, Changlin,Jiang, Liang,Lv, Kangle,Zhang, Zehui
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p. 264 - 273
(2017/06/23)
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- Magnetic nanoparticle-supported phosphine gold(i) complex: A highly efficient and recyclable catalyst for the direct reductive amination of aldehydes and ketones
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The direct reductive amination of aldehydes and ketones has been achieved in dichloromethane at room temperature by using a magnetic nanoparticle-supported phosphine gold(i) complex [Fe3O4@SiO2-P-AuCl] as the catalyst and ethyl Hantzsch ester as the hydrogen source, yielding a variety of secondary amines in excellent yields under neutral conditions. The new heterogeneous gold catalyst can be prepared by a simple procedure from commercially readily available reagents and can easily be separated from the reaction mixture by applying an external magnet and recycled at least 10 times without any loss of activity.
- Yang, Weisen,Wei, Li,Yi, Feiyan,Cai, Mingzhong
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p. 4554 - 4564
(2016/07/06)
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- One-pot synthesis of secondary amines from alcohols and nitroarenes on TiO2 loaded with Pd nanoparticles under UV irradiation
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Photoirradiation (λ > 300 nm) of TiO2 loaded with Pd nanoparticles (2 wt%, ca. 5 nm diameter) in water containing benzyl alcohol and nitrobenzene at room temperature successfully produces the corresponding secondary amine (N-benzylaniline) with 96% yield. This is achieved via three consecutive catalytic reactions: (i) photocatalytic oxidation of alcohol (aldehyde formation) and reduction of nitrobenzene (aniline formation); (ii) catalytic condensation of the formed aldehyde with aniline on the TiO2 surface (imine formation); and, (iii) photocatalytic hydrogenation of the formed imine (secondary amine formation). This catalytic system successfully produces several kinds of secondary amines, even those containing reducible substituents such as -CN, -COOH, or -CHO with >76% yields.
- Selvam, Kaliyamoorthy,Sakamoto, Hirokatsu,Shiraishi, Yasuhiro,Hirai, Takayuki
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p. 2467 - 2473
(2015/04/14)
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- Photocatalytic secondary amine synthesis from azobenzenes and alcohols on TiO2 loaded with Pd nanoparticles
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Photoirradiation (λ > 300 nm) of TiO2 loaded with Pd nanoparticles (ca. 2 wt%, 5 nm diameter) in water containing alcohols and azobenzene derivatives at room temperature successfully produces the corresponding secondary amines with high yields.
- Selvam, Kaliyamoorthy,Sakamoto, Hirokatsu,Shiraishi, Yasuhiro,Hirai, Takayuki
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p. 2856 - 2860
(2015/04/22)
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- Versatile synthesis of 4-spiro-β-lactam-3-carbonitriles via the intramolecular nucleophilic cyclization of N-(p-hydroxyphenyl)cyanoacetamides
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A series of 4-spiro-cyclohexadienonyl-β-lactam-3-carbonitriles, 2,7-dioxo-1-azaspiro[3.5]nona-5,8-diene-3-carbonitriles, was synthesized in satisfactory to excellent yields via the intramolecular nucleophilic cyclization of N-(p-hydroxyphenyl)cyanoacetamides with iodobenzene diacetate (IBD) as oxidant and potassium hydroxide as base. Acetic 4-spiro-cyclohexadienonyl- β-lactam-3-carbimidic anhydrides were obtained when organic base triethylamine was applied instead of potassium hydroxide. The mechanisms of the intramolecular nucleophilic cyclization and formation of acetic β-lactam-3-carbimidic anhydrides were proposed. The cyclization is a sequence of nucleophilic ipso addition and oxidative dearomatization. The formation of acetic carbimidic anhydrides is an acid-catalyzed acetate addition to the nitriles.
- Abdellaoui, Hassane,Xu, Jiaxi
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p. 4323 - 4330
(2014/06/10)
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- Highly practical iron-catalyzed C-O cleavage reactions
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Facile iron-catalyzed cleavage of various allyl, cinnamyl and benzyl C-O linkages has been effected in the presence of ethylmagnesium chloride. The protocol is operationally simple (xylene-THF, r.t., 1 h), requires low catalyst loading (1 mol% FeCl2) and tolerates halides, esters, amines, ethers and olefins. The allyl moiety is converted to volatile hydrocarbons which renders laborious product separation unnecessary.
- Gaertner, Dominik,Konnerth, Hannelore,Von Wangelin, Axel Jacobi
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p. 2541 - 2545
(2013/09/24)
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- Mild and efficient PtO2-catalyzed one-pot reductive mono-N-alkylation of nitroarenes
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(Chemical Equation Presented) A mild and efficient one-pot reductive monoalkylation of nitroarenes has been described using aldehydes as alkylating agents, molecular hydrogen as a reducing agent, and PtO2 as a catalyst in methanol. This methodology is found to be applicable for both aliphatic and aromatic aldehydes and for a wide variety of nitroarenes. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Commuications to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Sreedhar, Bojja,Rawat, Vikas S.
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experimental part
p. 2490 - 2502
(2012/07/14)
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- S-Benzyl isothiouronium chloride as a recoverable organocatalyst for the direct reductive amination of aldehydes
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The direct reductive amination of aldehydes using S-benzyl isothiouronium chloride as a recoverable organocatalyst for the activation of the imine intermediate through hydrogen bonding is described. A mild and operationally simple fragment coupling procedure was accomplished with a wide range of aldehydes as well as amines in good to excellent yields. In addition, the S-benzyl isothiouronium chloride catalyst was easily recovered by simple filtration and reused without any drop in its efficiency.
- Nguyen, Quynh Pham Bao,Kim, Taek Hyeon
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supporting information; experimental part
p. 5004 - 5007
(2011/10/07)
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- Two Component Recyclable Heterogeneous Catalyst, Process for Preparation Thereof and its Use for Preparation of Amines
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The invention describes the development of highly efficient, recyclable two component system, CuAl-hydrotalcite/rac 1,1′-Binaphthalene-2,2′-diol catalytic system for the N-alkylation of electron deficient aryl chlorides in presence of potassium carbonate as a base at room temperature in 3-6 h, wherein the process is provided for the preparation of various secondary amines via C—N coupling reaction of aliphatic amines(aliphatic open chain, acyclic, benzyl amines and heterocyclic amines) with various aryl chlorides.
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Page/Page column 5
(2012/01/13)
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- Selective alkylation of aminophenols
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O-or N-Alkylated derivatives of aminophenols are important synthetic intermediates in organic synthesis. A series of aminophenols were selectively alkylated on their hydroxyl group in good yields via benzaldehyde protection of the amino group, subsequent alkylation, and hydrolysis; or on their amino group via imination and following reduction. ARKAT USA, Inc.
- Wang, Renchao,Xu, Jiaxi
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experimental part
p. 293 - 299
(2010/10/02)
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- Highly active and selective supported iron oxide nanoparticles in microwave-assisted N-alkylations of amines with alcohols
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Highly active and stable supported iron oxide nanoparticles show excellent activities and switchable selectivities to target products in the microwave-assisted N-alkylation of amines with alcohols. The Royal Society of Chemistry 2010.
- Gonzalez-Arellano, Camino,Yoshida, Kenta,Luque, Rafael,Gai, Pratibha L.
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experimental part
p. 1281 - 1287
(2010/10/04)
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- PROLYL HYDROXYLASE ANTAGONISTS
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This invention relates to certain 2-[(quinolin-3-yl)carbonyl]aminoacetic acid derivatives of formula (I), where the various groups are defined herein, and which are useful in treating anemia.
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Page/Page column 41-42
(2010/11/26)
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- Chemoselective reductive amination of aldehydes and ketones by dibutylchlorotin hydride-HMPA complex
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Reductive amination of various aldehydes and ketones has been performed effectively by pentacoordinate chloro-substituted tin hydride complex, Bu2SnClH-HMPA. The tin reagent worked particularly well for the case using weakly basic aromatic amines as starting substrates. Stoichiometric amounts of a substrate and a reducing agent were adequate for the reaction. The Sn-Cl bond in the complex plays an important role for both steps of imine formation and subsequent reduction. Highly chemoselective reduction of carbonyls could be achieved regardless of other functionalities such as halogen, carbon- carbon double bond and hydroxyl groups in the starting carbonyls and amines.
- Suwa, Toshihiro,Sugiyama, Erika,Shibata, Ikuya,Baba, Akio
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p. 789 - 800
(2007/10/03)
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- Annulation Reactions with Iron(III) Chloride: Oxidation of Imines
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Aromatic imines react with phenylacetylene or styrene in an acetonitrile solution of iron(III) chloride to give quinolines 3 or their tetrahydro derivatives 11 together with variable amounts of products 4 arising from the reduction of the imines.The initial step appears to be a one-electron oxidation to generate iron(II) and an imine radical cation.When the reactions are carried out in the presence of stoichiometric amounts of tetrachloro-p-benzoquinone (chloranil), only quinolines 3 are obtained.
- Leardini, Rino,Nanni, Daniele,Tundo, Antonio,Zanardi, Giuseppe,Ruggieri, Fabrizio
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p. 1842 - 1848
(2007/10/02)
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- Selective Reduction of Imines with the Diborane-Methanol System
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The selective reduction of imines with diborane-methanol system was investigated.This system reduced imines quatitatively, and other functional groups tested were unaffected.Keywords-imine; diborane; selective reduction; diborane-methanol system; secondary amine; dimethoxyborane
- Nose, Atsuko,Kudo, Tadahiro
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p. 4817 - 4820
(2007/10/02)
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- Reduction of Imines Using NADH Models
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Reduction of substituted N-arylideneanilines (3) and NN'-bisarylidene-ethylenediamines (10) in glacial acetic acid takes place smoothly with 3,5-bis(eyhoxycarbonyl)-2,6-dimethyl-1,4-dihydropyridine (Hantzsch ester) (2) at room temperature in the dark.One-pot reductive amination of aromatic aldehydes in glacial acetic acid using (2) was equally efficient.Enamines (6)-(8) underwent reduction on protonation with trifluoroacetic acid in dichloromethane, but not in acetic acid.These reductions are analogous to NADH-mediated biochemical reductive aminations of carbonyl compounds.Imines (3) are also reduced to the corresponding amines (4) when irradiated with Pyrex-filtered light in the presence of (2) in benzene under nitrogen.This photoreduction also proceeds in the solid state and a two-phase system was successfully tested for recycling an NADH model for photoreduction of (3) using sunlight.
- Singh, Serjinder,Sharma, Vijay K.,Gill, Sarbjeet,Sahota, Ravjit Inder K.
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p. 437 - 440
(2007/10/02)
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- Method of topically treating inflammation
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This invention describes a method of treating inflammation in warmblooded animals by topically administering an effective amount of benzylamine and its derivatives.
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